English Royal Enfield Sport model 351. DIt os a 350cc OHV with JAP block made for RE of 1926. Rare motorcycle with fast JAP block. Last year that RE used JAP blocks. In 1927 they made their own blocks. This early block still has the open valves with ears. Unfinished restoration. Block has been renewed with new piston, new valves, springs, valve guides,... all nice and good but still needs valve springs on the piston. Other than that it is still about some tuning.